Three-Dimensional Plasma Printer

ABSTRACT

In one aspect, a method is described. The method may include ionizing a plasma gas to generate a plasma in a plasma source and accelerating the plasma toward a work surface. The method may further include adding a material to the plasma, thereby melting the material and accelerating the melted material toward the work surface. The method may further include depositing successive layers of the melted material on the work surface to form a three-dimensional object. Each of the successive layers may correspond to one of a number of planar slices of the three-dimensional object.

BACKGROUND

As computer-aided manufacturing has progressed, three-dimensional (3D)printing technology has developed to rapidly convert original designconcepts into physical models. A common technique for 3D printinginvolves additive manufacturing, in which successive layers of amaterial may be formed on top of each other. Each of the successivelayers may correspond with a cross-sectional layer of a 3D object, sothat the complete stack of successive layers forms the 3D object.

Typically, the successive layers may be formed from a resin with a lowmelting point. However, systems that utilize resin may require heatingelements to prevent the resin from cooling down too quickly andprematurely curing. Additionally, these systems may require thetemperature of the print head to be carefully maintained.

Other 3D printing systems may use laser sintering to selectively fusetogether successive layers of powdered waxes. However, laser systemshave a very narrow working area due to the small beam size of the laser.This often requires the laser to be scanned over a large area,increasing overall print times.

SUMMARY

In one aspect, a method is described. The method may include ionizing aplasma gas to generate a plasma in a plasma source and accelerating theplasma toward a work surface. The method may further include adding amaterial to the plasma, thereby melting the material and acceleratingthe melted material toward the work surface. The method may furtherinclude depositing successive layers of the melted material on the worksurface to form a three-dimensional object.

In a further aspect, a system is described. The system may include awork surface as well as a plasma source configured to generate a plasmaby ionizing a plasma gas and further configured to accelerate the plasmatoward the work surface. The system may further include a feederconfigured to add a material to the plasma, where the material is meltedby the plasma and accelerated toward the work surface. The system mayfurther include a controller configured to adjust the relative positionof the plasma to the work surface in order to deposit successive layersof the melted material on the work surface.

In a further aspect, an apparatus is described. The apparatus may be aprinting head apparatus for fabricating a three-dimensional object, andthe apparatus may include a first inlet configured to receive a plasmagas. The apparatus may further include a plasma source configured toionize the plasma gas to generate a plasma. The plasma source mayinclude an anode and a cathode configured to generate a direct currentarc plasma, a coil configured to generate an inductively coupled plasma,and capacitive electrodes configured to generate a capacitively coupledplasma. Further, the plasma source may be configured to accelerate theplasma toward a work surface. The apparatus may further include a secondinlet configured to receive a powdered printing material and add thepowdered printing material to the plasma, where the powdered printingmaterial is melted and deposited on the work surface to form athree-dimensional object.

These as well as other aspects, advantages, and alternatives will becomeapparent to those of ordinary skill in the art by reading the followingdetailed description with reference where appropriate to theaccompanying drawings. Further, it should be understood that thedescription provided in this summary section and elsewhere in thisdocument is intended to illustrate the claimed subject matter by way ofexample and not by way of limitation.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts a block diagram of a 3D plasma printing system, accordingto an example embodiment.

FIG. 2 depicts a block diagram of a 3D plasma printing system, accordingto an example embodiment.

FIG. 3 depicts a block diagram of a controller for a 3D plasma printingsystem, according to an example embodiment.

FIG. 4 depicts a 3D object and its cross-sectional planar slicesfabricated by a 3D plasma printing system, according to an exampleembodiment.

FIG. 5 depicts a plasma source of a 3D plasma printing system, accordingto an example embodiment.

FIG. 6 depicts a plasma source of a 3D plasma printing system, accordingto an example embodiment.

FIG. 7 depicts a flowchart of a method, according to an exampleembodiment.

DETAILED DESCRIPTION

Example methods and systems are described herein. Other exampleembodiments or features may further be utilized, and other changes maybe made, without departing from the scope of the subject matterpresented herein. In the following detailed description, reference ismade to the accompanying figures, which form a part thereof

The example embodiments described herein are not meant to be limiting.Thus, aspects of the present disclosure, as generally described hereinand illustrated in the figures, can be arranged, substituted, combined,separated, and designed in a wide variety of different configurations,all of which are explicitly contemplated herein.

Further, unless context suggests otherwise, the features illustrated ineach of the figures may be used in combination with one another. Thus,the figures should be generally viewed as component aspects of one ormore overall embodiments, with the understanding that not allillustrated features are necessary for each embodiment.

I. Overview

Illustrative embodiments relate to example three-dimensional (3D) plasmaprinters and corresponding control methods. The control methods may beused to operate the 3D plasma printer to fabricate 3D objects.

In an example arrangement, a 3D plasma printer may be embodied as aplasma source configured to generate a plasma and accelerate printingmaterial in a plasma jet toward a work surface.

In an example control method for the example arrangement, the 3D plasmaprinter may deposit successive layers of the printing material on thework surface. Each of the successive layers corresponds with a planarcross-section of a 3D object. By depositing the successive layers on topof one another, the 3D plasma printer may fabricate the 3D object fromthe printing material.

It should be understood that the above examples are provided forillustrative purposes, and should not be construed as limiting. As such,the method may additionally or alternatively include other features orinclude fewer features, without departing from the scope of theinvention.

II. Example Systems and Methods

FIG. 1 depicts a block diagram of a 3D plasma printing system 100according to an example embodiment. In particular, the 3D plasmaprinting system 100 includes a plasma source 110, a work surface 130, agas supply 140, a material supply 150, a power supply 160, one or moremotors 170, and a controller 180. The 3D plasma printing system 100 maybe configured to fabricate a 3D object on the work surface 130. The worksurface 130 may include a platform on which a 3D object is to befabricated, and/or the work surface 130 may include a 3D object itself.

In operation, the plasma source 110 may generate a plasma and acceleratethe plasma as a plasma jet 120 toward the work surface 130. To generatethe plasma, the plasma source 110 may ionize a gas from the gas supply140. The gas from the gas supply 140 may include a noble gas, oxygen,nitrogen, air, a reduced gas, or any other gas suitable for generatingthe plasma. Further, the gas supply 140 may supply the plasma source 110with more than one gas at a time. The plasma source 110 may contain thegas in a pressurized housing. The gas may be pressurized at a pressurebelow atmospheric pressure, above atmospheric pressure, or equal toatmospheric pressure.

To ionize the gas, the plasma source 110 may include various electrodes.For example, the plasma source 110 may include an anode and a cathodefor generating a direct current (DC) arc plasma, capacitive electrodesfor generating a capacitively coupled plasma, and/or a coil forgenerating an inductively coupled plasma. The power supply 160 may biasthe various electrodes in the plasma source 110 in order to ionize thegas. For example, the power supply 160 may provide a high voltage DCbias across the anode and cathode, and the power supply 160 may supply aradio frequency voltage signal to the capacitive electrodes and/or tothe coil.

The plasma source 110 may be configured to generate a plasma with avariable temperature. For example, the plasma source 110 may be capableof generating a plasma with a temperature in the range of 300 K to 6,000K.

The plasma source 110 may be configured to accelerate the plasma towardthe work surface 130. For example, the cathode may include an opening,and the electric field generated by the voltage bias across the anodeand cathode may accelerate the plasma through the cathode opening. Theplasma may be accelerated out of the plasma source 110 as a plasma jet120.

In some embodiments, the plasma source 110 may be a commercialatmospheric plasma jet-flow system, such as the GSL1100X-PJF.

The material supply 150 may provide printing material to be added to theplasma generated by the plasma source 110. The printing material maytake the form of a powder and may include various materials, such asceramics (e.g., aluminum oxide, zirconium oxide stabilized by yttriumoxide or calcium oxide, silicon dioxide, etc.), metals (e.g., tungsten,titanium, molybdenum, etc.), composite materials (e.g., tungstencarbide-cobalt, titanium carbide, etc.), and/or any combination thereof.The printing material may take other forms as well, such as gases usedfor plasma-assisted deposition (e.g., H₂ and CH₄ for diamonddeposition).

The printing material may be added to the plasma, either inside theplasma source 110 or to the plasma jet 120 outside the plasma source110. The plasma source 110 may be configured so that the temperature ofthe plasma is higher than a melting point of the printing material. Whenthe printing material is added to the plasma, the printing material maybe melted by the plasma and accelerated with the plasma toward the worksurface 130. The melted printing material may adhere to the work surface130 where it may cool and solidify. In some embodiments, before addingthe printing material to the plasma, the work surface 130 may be exposedto the plasma jet 120 in order to pre-treat, or heat, the work surface130. This may allow for better deposition of certain printing materialsthat may adhere more effectively to surfaces at elevated temperatures.

The one or more motors 170 may be configured to adjust the relativeposition of the plasma jet 120 and the work surface 130. In someembodiments, the work surface 130 may be stationary, and the one or moremotors 170 may be configured to adjust the position of the plasma source110. In other embodiments, the plasma source 110 may be stationary, andthe one or more motors 170 may be configured to adjust the position ofthe work surface 130. Still in other embodiments, the one or more motors170 may be configured to adjust both the position of the plasma source110 and the work surface 130.

The one or more motors 170 may take on various configurations and mayinclude DC motors, stepper motors, and/or servo motors, among others. Insome embodiments, the one or more motors 170 may be configured to adjustthe azimuth of the work surface 130 with respect to the plasma jet 120,for example, by rotating the work surface 130. In some embodiments, theone or more motors 170 may be configured to adjust the relative positionof the plasma jet 120 and the work surface 130 by moving the plasmasource 110 and/or the work surface 130 along x-, y-, and z-axes.

By adjusting the relative position of the plasma jet 120 and the worksurface 130, the melted printing material may be deposited on the worksurface in successive layers, and the successive layers may form afabricated 3D object. The 3D object may be fabricated by depositing theprinting material in stacked layers corresponding to a number ofcross-sectional slices of the 3D object, as discussed in more detailbelow with respect to FIG. 4.

In some embodiments, the 3D plasma printing system 100 may be configuredto apply a thermal spray coating to a real-world object on the worksurface 130. Rather than fabricating a 3D object from scratch, the 3Dplasma printing system 100 may deposit the melted printing material(e.g., metals, alloys, ceramics, plastics, composites, etc.) as acoating on the real-world object. The thermal spray coating may provideprotection against high temperatures, corrosion, erosion, wear, etc. Itmay also change the appearance, change the electrical or tribologicalproperties of the surface, replace worn material, etc.

In some embodiments, the 3D plasma printing system 100 may be configuredto etch a surface of a 3D object on the work surface 130. By exposingthe 3D object to the plasma jet 120 without adding printing material tothe plasma, the plasma may etch away particles at the surface of the 3Dobject. Plasma etching may be used to clean surfaces, for example byremoving an oxide layer, alter surface textures, and/or processsemiconductor materials, among other uses. Further, by utilizing plasmaetching, the 3D plasma printing system 100 may employ subtractivemanufacturing techniques to fabricate 3D objects, unlike conventional 3Dprinters, which are limited to additive techniques.

In some embodiments, the 3D plasma printing system 100 may be configuredto sputter a surface of a 3D object on the work surface 130. Sputteringis a process in which particles are ejected from a solid target materialdue to bombardment of the target by the plasma ions. The plasma source110 may be configured to accelerate the plasma toward a target materialproximal to the 3D object. The target material may include a metal, analloy, an oxide, various compounds, or any other material suitable forsputtering. By bombarding the target material with the plasma from theplasma source 110, the target material may be sputtered onto the 3Dobject. This process may be used, for example, to deposit a thin layerof the target material on the 3D object.

The gas supply 140, power supply 160, material supply 150, and one ormore motors 170 may be coupled to the controller 180 to facilitate theiroperation in accordance with the methods and processes disclosed herein,as discussed in more detail below with respect to FIG. 3.

FIG. 2 depicts a block diagram of another 3D plasma printing system 200according to an example embodiment. The 3D plasma printing system 200 issimilar to3D plasma printing system 100, however 3D plasma printingsystem 200 includes a pressurized housing 210 and illustrates thematerial supply 150 and one or more motors 170 in more detail.

As depicted in FIG. 2, the plasma source 110 and the work surface 130may be located in a pressurized housing 210. The pressurized housing 210may be any container, such as a vacuum chamber, capable of containing apressurized gas. The pressurized housing 210 may receive gas from thegas supply 140 and may be coupled to a pump (not shown). In someembodiments, the pump may be configured to pump gas into the pressurizedhousing 210 at a pressure above atmospheric pressure (e.g., above 760mTorr). In some embodiments, the pump may be configured to pump gas outof the pressurized housing 210 at a pressure below atmospheric pressure(e.g., below 760 mTorr).

As further depicted in FIG. 2, the material supply 150 may include ahopper 252. The hopper 252 may contain a number of cartridges, eachcartridge capable of containing a different powdered printing materialand/or powdered printing materials of different colors and/or textures.Powdered printing material from one or more of the cartridges may be fedfrom the hopper 252 into a blender 254. The blender 254 may blend thepowdered printing materials from the hopper 252 to create a mixture ofpowdered printing materials. The mixed powder may be transported fromthe blender 254 to the plasma source 110 by a powder feeder 256.

The powder feeder 256 may be any commercial or proprietary powder feedercapable of adding the powdered printing material to the plasma at aconsistent rate without agglomeration, such as the FST PF-50 powderfeeder. The powder feeder 256 may use gravity as well as pressurized gasto deliver the powdered printing material to the plasma source 110. Inthe powder feeder 256, powdered printing material may be fed from ahopper to a gas fluidization area. A carrier gas may pass through thefluidization area, fluidizing the printing material and transporting thefluidized printing material to the plasma source 110. In someembodiments, the carrier gas may be the same gas as the ionized plasmagas in the plasma source 110 from the gas supply 140. The flow rate ofthe powdered printing material supplied to the plasma source 110 may beincreased by increasing the differential pressure of the carrier gas tothe fluidization area.

The powder feeder 256 may transport the fluidized powdered printingmaterial to the plasma source 110 through a probe. The probe may beconfigured to add the powdered printing material to the plasma insidethe plasma source 110 and/or to the plasma jet 120 outside the plasmasource 110. The probe may be a liquid-cooled probe, such as awater-cooled probe. In some embodiments, more than one probe may be usedto simultaneously transport more than one powdered printing material tothe plasma.

As further depicted in FIG. 2, the one or more motors 170 may include anx-axis motor 272 and a y-axis motor 274 coupled to the plasma source 110and a z-axis motor 276 coupled to the work surface 130. The x-axis motor272 may be configured to move the plasma source 110 along an x-axisparallel to the work surface 130, the y-axis motor 274 may be configuredto move the plasma source 110 along a y-axis parallel to the worksurface 130, and the z-axis motor 276 may be configured to move the worksurface 130 along a z-axis perpendicular to the work surface 130. Thez-axis motor 276 may further be configured to rotate the work surface130 around the z-axis.

In order to carry out the methods, processes, or functions disclosed inthis specification or the accompanying drawings, the controller 180 mayinclude computing device components. FIG. 3 depicts an exampleembodiment 300 of computing device components (e.g., functional elementsof a computing device) that may be included in the controller 180.

The controller computing device components 300 may include one or moreprocessors 302, data storage 304, program instructions 306, and aninput/output unit 308, all of which may be coupled by a system bus or asimilar mechanism. The one or more processors 302 may include one ormore central processing units (CPUs), such as one or more generalpurpose processors and/or one or more dedicated processors (e.g.,application specific integrated circuits (ASICs) or digital signalprocessors (DSPs), etc.). The one or more processors 302 can beconfigured to execute computer-readable program instructions 306 thatare stored in the data storage 304 and are executable to provide atleast part of the functionality described herein.

The data storage 304 may include or take the form of one or morecomputer-readable storage media that may be read or accessed by at leastone of the one or more processors 302. The one or more computer-readablestorage media can include volatile and/or non-volatile storagecomponents, such as optical, magnetic, organic, or other memory or discstorage, which may be integrated in whole or in part with at least oneof the one or more processors 302. In some embodiments, the data storage304 may be implemented using a single physical device (e.g., oneoptical, magnetic, organic, or other memory or disc storage unit), whilein other embodiments, the data storage 304 may be implemented using twoor more physical devices.

The input/output unit 308 may include user input/output devices, networkinput/output devices, and/or other types of input/output devices. Forexample, input/output unit 308 may include user input/output devices,such as a touch screen, a keyboard, a keypad, a computer mouse, liquidcrystal displays (LCD), light emitting diodes (LEDs), displays usingdigital light processing (DLP) technology, cathode ray tubes (CRT),light bulbs, and/or other similar devices. Network input/output devicesmay include wired network receivers and/or transceivers, such as anEthernet transceiver, a Universal Serial Bus (USB) transceiver, orsimilar transceiver configurable to communicate via a twisted pair wire,a coaxial cable, a fiber-optic link, or a similar physical connection toa wireline network, and/or wireless network receivers and/ortransceivers, such as a Bluetooth transceiver, a Zigbee transceiver, aWi-Fi transceiver, a WiMAX transceiver, a wireless wide-area network(WWAN) transceiver and/or other similar types of wireless transceiversconfigurable to communicate via a wireless network.

The controller computing device components 300 may be implemented inwhole or in part in various components of the 3D plasma printing systemsdepicted in FIGS. 1 and 2 and/or in at least one device remotely locatedfrom the 3D plasma printing systems, such as a workstation or personalcomputer. Generally, the manner in which the controller 180 isimplemented may vary, depending upon the particular application.

In order to fabricate a 3D object, a computing device, such as thecontroller 180, may be provided with 3D object data indicative of the 3Dobject to be printed. The 3D object data may indicate various physicaldimensions of the 3D object, such that the 3D object data isrepresentative of a physical volume of space that will be occupied bythe printed 3D object.

In some embodiments, the 3D object data may be generated by a 3Dscanner. A 3D scanner may analyze a real-world object to collect data onits shape and/or appearance. For example, some 3D scanners, such ascoordinate measuring machines, may probe the real-world object withphysical touch to generate 3D object data. Other 3D scanners (e.g.,time-of-flight laser scanners, triangulation laser scanners, conoscopicsystems, structured light scanners, modulated light scanners, etc.) mayemit some kind of radiation or light and detect its reflection or theradiation passing through the real-world object. And other 3D scannersthat employ, for example, stereoscopic systems, photometric systems, orsilhouette techniques, among others, do not emit any kind of radiationthemselves, but instead rely on detecting reflected ambient radiation.

In some embodiments, the 3D object data may be generated from scratchthrough, for example, a computer-aided design (CAD) software. It shouldbe understood that generation of the 3D object data is not limited tothe methods disclosed herein, rather any conventional methods may beused to generate the 3D object data.

In some embodiments, the 3D object data may be scaled to increase ordecrease the size of the printed 3D object. Further, the 3D object datamay be divided into subparts, each of the subparts corresponding to apiece of the 3D object, which may be fabricated by assembling theprinted pieces. This may allow fabrication of more complex and/or larger3D objects than the 3D plasma printing system may otherwise be capableof fabricating.

The controller 180 may parse the 3D object data representing the entire3D object into 3D object data representing a number of cross-sectionalplanar slices of the 3D object. The number of slices may depend on thedesired thickness of each cross-sectional slice as well as theresolution capabilities of the 3D plasma printing system. The resolutionof the 3D plasma printing system represents how thin each layer ofprinting material deposited by the printing system is. The resolutionmay be used to determine the dimensions of the planar slices of the 3Dobject. For example, the controller 180 may parse the 3D object datainto planar slices with a thickness equal to or greater than a minimumthickness. The minimum thickness may depend on a processing time, a flowrate of the powder from the material supply 150, and/or a particle sizeof the powder added to the plasma. For example, a typical particle sizeof the powder may be 5 to 500 microns, and a typical resolution may be 1to 500 microns.

To fabricate the 3D object, the 3D plasma printing system may beconfigured to deposit successive layers of printing material on top ofone another on the work surface, each of the successive layerscorresponding to one of the number of planar slices of the 3D object.

In some embodiments, the 3D object data may further include dataindicating a color or material of all or part of the 3D object to beprinted. Based on this data, the controller 180 may select one or morepowdered printing materials of a corresponding color or material fromthe material supply 150 to be deposited on the work surface 130 as allor part of one or more of the cross-sectional planar slices of the 3Dobject.

FIG. 4 depicts an example embodiment 400 of a 3D object 402 and a numberof cross-sectional planar slices 404 of the 3D object 402 printed by a3D plasma printing system. As depicted in FIG. 4, the 3D object 402 maytake on various forms, such as a cone. To fabricate the cone 402, thecontroller 180 may be provided with 3D object data indicative of thecone 402. The 3D object data may indicate various physical dimensions ofthe cone 402, such as its height and the radius of its base. Based onthe physical dimensions of the cone 402, the controller 180 may parsethe 3D object data into data representing the cross-sectional planarslices 404. The controller 180 may control the one or more motors 170 toadjust the relative position of the plasma jet 120 and the work surface130 so that printing material is added to the plasma and deposited onthe work surface in patterns corresponding to each of the slices 404. Bydepositing the printing material on the work surface 130 in successivelayers, one on top of another, the 3D plasma printing system mayfabricate the cone 402.

FIG. 5 depicts a cross-sectional view of a plasma source 500 of a 3Dplasma printing system, according to an example embodiment. The plasmasource 500 may take the form of or be similar in form to the plasmasource 110 depicted in FIGS. 1 and 2. The plasma source 500 may beconfigured to generate a plasma 502 and accelerate the plasma 502 out ofthe plasma source 500 as a plasma jet 504 and may include a housing 506,an anode 508, a cathode 510, capacitive electrodes 512, a coil 514, agas inlet 516, and a printing material inlet 518.

The plasma source 500 may generate the plasma 502 within the housing506. The housing 506 may be made of any non-conductive material, such asquartz, a ceramic, or some other dielectric material. The anode 508 andcathode 510 may be located inside the housing 506 at or near opposingends of the housing 506. The capacitive electrodes 512 may be located onthe outside surface of the housing 506 at or near opposing ends of thehousing 506. The coil 514 may be wound around the length of the housing506 on the outside surface of the housing 506 between the capacitiveelectrodes 512.

Gas may flow into the housing 506 through the gas inlet 516. The gas maybe provided by a gas supply, such as the gas supply 140 depicted inFIGS. 1 and 2, and may include a noble gas, oxygen, nitrogen, air, areduced gas, or any other gas suitable for generating a plasma. Asdepicted in FIG. 5, the gas inlet 516 may be located at or near the endof the housing 506 opposite the plasma jet 504. In some embodiments, thegas inlet 516 may provide gas to the housing 506 at various otherlocations.

The gas supplied to the housing 506 may be ionized by coupling thevarious electrodes 508-514 to a power supply (not shown), such as thepower supply 160 depicted in FIGS. 1 and 2. The power supply may providea DC voltage bias across the anode 508 and cathode 510. By configuringthe DC voltage bias to be sufficiently large and/or by varying thepressure of the gas in the housing 506, the electric field between theanode 508 and cathode 510 may ionize the gas, generating a DC arcplasma.

The power supply may further provide a radio frequency (RF) signalacross the capacitive electrodes 512. The capacitive electrodes 512 maybe capacitively coupled to the plasma 502. The RF signal across thecapacitive electrodes 512 exposes the electrons and ions in the plasma502 to a time-varying electric field, causing the particles to oscillateback and forth between the capacitive electrodes 512. The oscillationsresult in particle collisions that further ionize the gas, generating acapacitively coupled plasma.

Similarly, the power supply may further provide an RF signal to the coil514. The RF signal across the coil 514 exposes the electrons and ions inthe plasma 502 to a time-varying magnetic field, which in turn inducesan azimuthal electric field in the gas. This causes electrons in the gasto travel in figure-eight trajectories, resulting in particle collisionsthat further ionize the gas and generating an inductively coupledplasma.

In some embodiments, the plasma source 500 may be configured to onlygenerate one of a DC arc plasma, a capacitively coupled plasma, or aninductively coupled plasma. In some embodiments, the plasma source 500may be configured to generate a combination of two or all three of a DCarc plasma, a capacitively coupled plasma, and an inductively coupledplasma.

The plasma source 500 may be further configured to accelerate a portionof the generated plasma out of the plasma source 500 in a plasma jet504. As depicted in FIG. 5, the cathode 510 may include an opening, andthe electric field between the anode 508 and cathode 510 may acceleratethe plasma 502 through the opening, forming the plasma jet 504.

Printing material may be added to the plasma 502 through the printingmaterial inlet 518. The printing material may be provided by a materialsupply, such as the material supply 150 depicted in FIGS. 1 and 2. Asdiscussed above, the printing material may take the form of a powder andmay include various materials, such as ceramics (e.g., aluminum oxide,zirconium oxide stabilized by yttrium oxide or calcium oxide, silicondioxide, etc.), metals (e.g., tungsten, titanium, molybdenum, etc.),composite materials (e.g., tungsten carbide-cobalt, titanium carbide,etc.), and/or any combination thereof. The printing material may takeother forms as well, such as gases used for plasma-assisted deposition(e.g., H₂ and CH₄ for diamond deposition). The printing material inlet518 may be configured to receive more than one printing material at atime through one or more liquid-cooled probes.

As depicted in FIG. 5, the printing material inlet 518 may be located atthe end of the plasma source 500 opposite the plasma jet 504. However,in some embodiments, the printing material inlet 518 may be located atvarious locations along the length of the plasma source 500.

For powdered printing materials, the temperature of the plasma 502 maybe configured to be higher than a melting temperature of the printingmaterial. The temperature of the plasma 502 may be varied by adjustingthe power delivered to the plasma 502, for example, by increasing thevoltage supplied to the various electrodes 508-514 or by varying thepressure of the gas within the housing 506. In some embodiments, theplasma 502 may have a temperature that is variable between 300 K and6,000 K.

By configuring the temperature of the plasma 502 to be higher than themelting temperature of the printing material, the printing material maybe melted when it is added to the plasma 502 through the printingmaterial inlet 518. The melted printing material may be accelerated outof the plasma source 500 along with the plasma 502 in the plasma jet504.

FIG. 6 depicts a plasma source 600 of a 3D plasma printing system,according to an example embodiment. The plasma source 600 is similar toplasma source 500, however plasma source 600 includes a printingmaterial inlet 602 configured to add printing material directly to theplasma jet 504. Similar to the plasma source 500 depicted in FIG. 5, theprinting material may be supplied to the printing material inlet 602 bya material supply, such as the material supply 150 depicted in FIGS. 1and 2. The printing material inlet 602 may be configured to receive morethan one printing material at a time through one or more liquid-cooledprobes.

FIG. 7 depicts a flowchart of an example method 700 that could be usedto print a 3D object. The example method 700 may include one or moreoperations, functions, or actions, as depicted by one or more of blocks702, 704, 706, and/or 708, each of which may be carried out by any ofthe systems described by way of FIGS. 1-6; however, other configurationscould be used as well.

Furthermore, those skilled in the art will understand that the flowchartdescribed herein illustrates functionality and operation of certainimplementations of example embodiments. In this regard, each block ofthe flow diagram may represent a module, a segment, or a portion ofprogram code, which includes one or more instructions executable by aprocessor for implementing specific logical functions or steps in theprocess. The program code may be stored on any type of computer readablemedium, for example, such as a storage device including a disk or harddrive. In addition, each block may represent circuitry that is wired toperform the specific logical functions in the process. Alternativeimplementations are included within the scope of the example embodimentsof the present application in which functions may be executed out oforder from that shown or discussed, including substantially concurrentor in reverse order, depending on the functionality involved, as wouldbe understood by those reasonably skilled in the art.

Method 700 begins at block 702, which includes ionizing a plasma gas togenerate a plasma in a plasma source. The plasma gas may include a noblegas, oxygen, nitrogen, air, a reduced gas, or any other gas suitable forgenerating the plasma. The plasma source may include an anode andcathode for generating a DC arc plasma, capacitive electrodes forgenerating a capacitively coupled plasma, and/or a coil for generatingan inductively coupled plasma.

Method 700 continues at block 704, which includes accelerating theplasma toward a work surface. An electric field resulting from a voltagebias across the anode and cathode of the plasma source may acceleratethe plasma through an opening in the cathode, forming a plasma jet. Theplasma source may be positioned above the work surface so the worksurface is exposed to the plasma jet.

Method 700 continues at block 706, which includes adding a material tothe plasma, thereby melting the material and accelerating the meltedmaterial toward the work surface. The material may take the form of apowder and may include various materials, such as ceramics (e.g.,aluminum oxide, zirconium oxide stabilized by yttrium oxide or calciumoxide, silicon dioxide, etc.), metals (e.g., tungsten, titanium,molybdenum, etc.), composite materials (e.g., tungsten carbide-cobalt,titanium carbide, etc.), and/or any combination thereof. The materialmay take other forms as well, such as gases used for plasma-assisteddeposition (e.g., H₂ and CH₄ for diamond deposition). The material maybe added to the plasma within the plasma source, and/or the material maybe added to the plasma jet outside the plasma source.

Method 700 continues at block 708, which includes depositing successivelayers of the melted material on the work surface to form a 3D object.Each of the successive layers may correspond with a planar slice of the3D object. By depositing the successive layers on top of one another,the 3D object may be formed with the printing material.

In addition to the operations depicted in FIG. 7, other operations maybe utilized with the example 3D plasma printing systems presentedherein.

III. Conclusion

The particular arrangements shown in the Figures should not be viewed aslimiting. It should be understood that other embodiments may includemore or less of each element shown in a given Figure. Further, some ofthe illustrated elements may be combined or omitted. Yet further, anexemplary embodiment may include elements that are not illustrated inthe Figures.

Additionally, while various aspects and embodiments have been disclosedherein, other aspects and embodiments will be apparent to those skilledin the art. The various aspects and embodiments disclosed herein are forpurposes of illustration and are not intended to be limiting, with thetrue scope and spirit being indicated by the following claims. Otherembodiments may be utilized, and other changes may be made, withoutdeparting from the spirit or scope of the subject matter presentedherein. It will be readily understood that the aspects of the presentdisclosure, as generally described herein, and illustrated in thefigures, can be arranged, substituted, combined, separated, and designedin a wide variety of different configurations, all of which arecontemplated herein.

What is claimed is:
 1. A method comprising: ionizing a plasma gas togenerate a plasma in a plasma source; accelerating the plasma toward awork surface; adding a material to the plasma, thereby melting thematerial and accelerating the melted material toward the work surface;and depositing successive layers of the melted material on the worksurface to form a three-dimensional object.
 2. The method of claim 1,wherein depositing successive layers of the melted material on the worksurface to form the three-dimensional object comprises: parsingthree-dimensional object data indicative of the three-dimensional objectto be printed into cross-section object data indicative of a pluralityof planar slices of the three-dimensional object; and depositingsuccessive layers of the melted printing material on the work surface,each of the successive layers corresponding to one of the plurality ofplanar slices of the three-dimensional object.
 3. The method of claim 1,wherein the material comprises a material selected from the groupconsisting of a ceramic powder, a metal powder, and a composite materialpowder.
 4. The method of claim 1, wherein the material comprises a firstpowder and a second powder, wherein the first and second powders areblended before adding the material to the plasma.
 5. The method of claim1, wherein adding the material to the plasma comprises: fluidizing thematerial with the carrier gas; and feeding the fluidized material to theplasma through a liquid-cooled probe.
 6. The method of claim 5, whereinthe fluidized material is added to the plasma inside the plasma source.7. The method of claim 5, wherein the fluidized material is added to theplasma outside the plasma source into a plasma jet.
 8. The method ofclaim 5, wherein the liquid-cooled probe comprises a water-cooled probe.9. The method of claim 1, further comprising, prior to adding thematerial to the plasma, exposing the work surface to the plasma to etchthe work surface.
 10. The method of claim 1, wherein the plasmacomprises inductively coupled plasma.
 11. The method of claim 1, whereinthe plasma comprises capacitively coupled plasma.
 12. The method ofclaim 1, wherein the plasma comprises direct current arc plasma.
 13. Themethod of claim 1, wherein the plasma has a temperature that is variablebetween 300 kelvin and 6,000 kelvin.
 14. A system comprising: a worksurface; a plasma source configured to generate a plasma by ionizing aplasma gas and to accelerate the plasma toward the work surface; afeeder configured to add a material to the plasma, wherein the materialis melted and accelerated toward the work surface; and a controllerconfigured to adjust the relative position of the plasma to the worksurface to deposit successive layers of the melted material on the worksurface.
 15. The system of claim 14, wherein adjusting the relativeposition of the plasma to the work surface to deposit successive layersof the melted material on the work surface comprises: parsingthree-dimensional object data indicative of a three-dimensional objectto be printed into cross-section object data indicative of a pluralityof planar slices of the three-dimensional object; and adjusting therelative position of the plasma to the work surface to depositsuccessive layers of the melted material on the work surface, each ofthe successive layers corresponding to one of the plurality of planarslices of the three-dimensional object.
 16. The system of claim 14,wherein the plasma source is further configured to etch the work surfaceby exposing the work surface to the plasma prior to the feeder addingthe material to the plasma.
 17. A printing head apparatus forfabricating a three-dimensional object comprising: a first inletconfigured to receive a plasma gas; a plasma source configured to ionizethe plasma gas to generate a plasma, wherein the plasma source comprisesan anode and cathode configured to generate a direct current arc plasma,a coil configured to generate an inductively coupled plasma, andcapacitive electrodes configured to generate a capacitively coupledplasma, wherein the plasma source is configured to accelerate the plasmatoward a work surface; and a second inlet configured to receive apowdered printing material and add the powdered printing material to theplasma, wherein the powdered printing material is melted and depositedon the work surface to form a three-dimensional object.
 18. Theapparatus of claim 17, wherein the plasma gas comprises a noble gas. 19.The apparatus of claim 17, wherein the plasma gas comprises oxygen. 20.The apparatus of claim 17, wherein the plasma gas comprises a reducedgas.
 21. The apparatus of claim 17, wherein the apparatus is containedwithin a pressurized housing, wherein the housing is pressurized at apressure below atmospheric pressure.
 22. The apparatus of claim 17,wherein the apparatus is contained within a pressurized housing, whereinthe housing is pressurized at atmospheric pressure.
 23. The apparatus ofclaim 17, wherein the apparatus is contained within a pressurizedhousing, wherein the housing is pressurized at a pressure aboveatmospheric pressure.